This invention relates generally to packaging machines and, more particularly, to a method and apparatus for package labeling in such machines wherein labels are applied to sections of wrapping material prior to packages being wrapped therein.
A number of package wrapping machines are well known and used, for example, in supermarkets for packaging meats, produce and other food items. Such wrapping machines may provide at least two different widths of wrapping material to accommodate a large variety of package sizes. The wrapping material is provided in continuous rolls of different widths such that the length and width of sheets of wrapping material may be selected for wrapping packages. The length and width of a sheet of wrapping material to be used for a given package may be selected by the operator based on the package to be wrapped or may be automatically selected based on machine-sensed dimensions of the package.
Computing weighing scales and labelers which print and apply price labels to packages are oftentimes associated with wrapping machines. A computer or other electronic means is included within the scale or labeler for calculating prices for the packages. Prices are calculated by multiplying the net weight of a package times the price per unit weight of the commodity within the package, the unit price having been previously stored into a memory of the computer. Commodity net weight is determined by compensating for the tare weight or weight of the packaging material.
In the operation of a prior art packaging system, a commodity to be packaged is initially placed onto a supporting tray. The trayed commodity or package is then fed into the wrapping machine where a sheet of packaging material, typically transparent stretch film, is wrapped about the package and secured beneath the tray. The wrapped package is then conveyed either mechanically or manually to a combination scale and labeler. At the scale and labeler, the price of the package is computed, a price label is printed and the label is applied to the package.
In order to conserve space, packaging systems have combined a weighing scale, a wrapping machine and a label printer into a single unit. See, for example, Teraoka, U.S. Pat. No. 4,415,048, wherein a trayed commodity is initially placed onto a weighing scale which forms the input of a wrapping machine. The trayed commodity is weighed, wrapped and passed to a package outlet passage along which a labeler is positioned to generate a pricing label and apply the label to the wrapped package. In the Teraoka packaging system, labels are printed and applied downstream from the wrapping station along a wrapped package outlet passage such that labeling information must be stored and delayed or large gaps must be placed between consecutive packages for labels to correspond correctly to wrapped packages. Package labeling is also effected along a package outlet passage in an integrated packaging machine disclosed in Fine, U.S. Pat. Nos. 4,458,470 and 4,548,024.
To overcome the problems created by having to store and delay the weight signals of packages or the packages themselves progressing through a packaging machine, an improved packaging system is disclosed in Boshinski, U.S. Pat. No. 4,543,766, which is incorporated herein by reference. In the Boshinski packaging system, the wrapping machine is an elevator-type machine presently quite popular in the supermarket industry. A labeler is positioned over the elevator and a weighing conveyor extends between a package feed-in tray and the elevator such that a package is weighed as it is conveyed to the elevator, a label is printed and applied to the package as the package is wrapped, by elevation into a sheet of wrapping material.
Package labeling over the elevator of an elevator-type machine is also disclosed in Treiber, U.S. Pat. No. 4,615,757. In the Treiber system, labeling apparatus is shifted horizontally relative to the wrapping machine for positioning labels within selected labeling regions on packages which are labeled as the packages are wrapped.
In all of the known prior art labeling arrangements for such machines, labels are applied either to fully wrapped packages or to packages as they are being wrapped such that the labels are applied to an upper package surface which oftentimes is lumpy or irregular. Application of labels to such surfaces can lead to incomplete label adhesion, wrinkled labels which may affect scannability when UPC codes are used, and/or could even pierce the wrapping material if a sharp bone edge or the like is struck by the label applicator. Hence, the need exists for an improved method and apparatus for package label application which overcomes these problems of the prior art.